A LOOK AT GLIDING AND UNDERWATER KICKING IN THE SWIM TURN

A series of studies were conducted to examine hydrodynamic drag throughout the gliding and stroke preparation phases of the freestyle tumble turn. The first study examined the effects of velocity and depth on the passive drag forces and demonstrated that significant drag reduction benefits were found with the swimmers performing glides underwater when compared to gliding at the water surface. The second study sought to establish the appropriate velocity for initiating underwater kicking, as well as the most efficient gliding position and kicking technique. The results indicate that swimmers should initiate underwater kicking at between 1.9 and 2.2 ms-1. No significant differences were found between two streamline glide positions, and similarly, between three underwater kicking styles. The results of these studies present strategies for reducing the drag forces experienced by swimmers throughout the freestyle turn

Progress in Precursor Skills and Front Crawl Swimming in Children With and Without Developmental Coordination Disorder

This study investigated swimming performance and the influence of task complexity among children with and without Developmental Coordination Disorder (DCD). Two groups of children were matched by age - 11 controls without DCD and 11 children with DCD. Repeated measures ANOVA showed that children with DCD performed significantly lower level than age-matched controls for all the water competency tasks and front crawl. Both groups improved significantly in water competency and front crawl over 10 lessons. Significant interactions suggested that children with DCD showed different rates of change during the acquisition of the glide and front crawl. Both groups regressed with increased task complexity. Awareness of motor learning difficulties experienced by children enables teachers, parents, and children to have realistic expectations. A supportive environments for children with DCD will enable them to achieve the important swimming skill competencies and reduce drop-out rates in learn-to-swim programs

Jumping Abilities and Swimming Grab-Start Performances in Elite and Recreational Swimmers

This study examined the relationships between the performances of a swimming grab start and each of countermovement jump for distance, countermovement jump for height, squat jump for distance and squat jump for height. Nine elite and 7 recreational female swimmers performed 6 trials in each of the 4 jumping techniques, and six 25-m freestyle sprints following a grab start. Elite subjects performed significantly better in the start performances, and this was attributed to the greater horizontal impulse. Correlations in the elite group revealed that grab-start performance was not related to performances of any jumps. This suggests that the grab start is independent of the jumping techniques for this group, and performance of one skill may not translate to performance in the other. Significant correlations were found between performances of the grab start and the f4 jumps in the recreational group, possibly because of adoption of an “incorrect” motor pattern that may be similar to those of the jumps. This study highlighted the importance of practicing the start as a whole skill during training

Effects of Teaching Methods on Swimming Skill Acquisition in Children with Developmental Coordination Disorder

This study compared the delivery of “verbal and visual” with “verbal, visual and tactile” swimming instruction to small groups of DCD pupils for front crawl and backstroke performance across 10 lessons x 30 minutes/week. The interaction and main effects for group and time on front crawl performances were not significant, indicating no differences were found between the two teaching methods. Also, the front crawl performances of the DCD swimmers did not change over the intervention period. The interaction and main effect for group on backstroke performances over the 10 weekly lessons were not significant. However, a significant main effect of time was found with backstroke changes found between Weeks 1 and 10 and Weeks 6 and 10. Sub-component analyses for horizontal body position, head position and breathing, and use of the lower limbs, revealed significant time effect improvements, but only between Weeks 1 and 10. Hence, both DCD groups improved their backstroke performances at the same rate across the 10 week intervention, despite being exposed to different instructional method

The Relationship Between Stride Rates, Lengths and Body Size and their Affect on Elite Triathletes’ Running Performance During Competition

Previous research has suggested that a degree of predictability exists in the relationship between self-selected running stride rates (SR) and stride lengths (SL) with measures of body size such as mass, height and limb lengths. Significant correlations have also been revealed between these body size measures and performance and between SL and performance. However, there is also evidence to suggest that triathlon performance may be related to maintaining a longer SL during the final run. Hence, the aim of this investigation was to examine whether there was any relationship between SR and SL, with body masses and heights of senior elite triathletes during the run stage of a triathlon. The SRs and SLs of 37 male senior elite Triathlon World Championships competitors were analysed via videography and Video Expert II Coach. These values were correlated with the athletes’ body masses and heights (p\u3c0.01). The results indicated a limited relationship between height and mass with SR in the early stages of the run. However, a significant, positive correlation existed between SL and height at all points from 3 km to the end of the run. Those triathletes who were taller used longer strides. Further research is warranted to examine the effects of cycling on the subsequent run discipline during triathlon and if body size and shape of triathletes have evolved as the young sport of triathlon develops

FORCE DEVELOPMENT PROFILE OF THE LOWER LIMBS IN THE GRAB AND TRACK START IN SWIMMING

Left and right ground reaction forces of 9 male and 7 female national and international level swimmers were measured during grab and track starts. Analysis of temporal, kinetic and velocity measures indicated that while swimmers left the block faster in the track start, grab starts enabled swimmers to generate greater vertical impulses and take-off velocities. No significant differences were found in the horizontal impulses and the time to 6m between the two starts. Left and right force profiles were examined qualitatively to identify key points related to force development strategies and lateral asymmetr

Cadence, Stride Rate and Stride Length During Triathlon Competition

Triathlon research shows cycling alters the physiological response of subsequent running but, at present, biomechanical changes are unresolved. This study examined cycling cadence and running stride rate (SR) and length (SL) used by senior elite triathletes during competition. These variables were then compared to running and triathlon performance. Data from 51 elite male World Championships triathletes were analysed via video recordings and Video Expert II Coach. Triathletes revealed consistent cadences throughout the majority of the cycle (96.8 +2.7 rpm) and run (90.9 +2.4 rpm) disciplines. However, a cadence increase (99.6 +5.7 rpm) was recorded at the completion of the cycle prior to running. Running SR and SL was significantly lower at the end of the run indicating a level of fatigue (p\u3c0.01). Running SL was significantly and positively correlated with running and triathlon performance (p\u3c0.01) suggesting those that could maintain a longer SL had a faster run and better final finishing position

Home Swimming Pool Design to Improve Diving Safety

This study sought to establish home swimming pool design guidelines to minimize risk of diving injury. Using a qualitative design, interviews with representatives of home pool companies were analyzed and common themes were determined. Pool company display centers and advertising materials were also examined. The typical in-ground fiberglass home pool was described by manufacturers as 8m in length, with a constant gradient of 0.9m to 1.8–2.0m deep. Comparisons between this profile and the underwater pathways of young adults in previous studies by the authors showed that, if the dives had been performed in this typical pool, impact would have occurred for some dives. Safety features such as depth markings and signage were absent from all pools. We concluded that recreational swimmers with limited diving skills are at risk of diving injury in the typical home swimming pool. Recommendations are provided of strategies that can be implemented by home pool owners to improve pool safety

MORPHOLOGY AND HYDRODYNAMIC RESISTANCE IN YOUNG SWIMMERS

Morphology and hydrodynamic drag were measured of 6 males and 6 females, from each of the 9, 11 and 13 yr age groups. Net forces were examined when towing swimmers while prone streamlined gliding and flutter kicking at 1.3 to 2.5 ms-1. The passive drag force at 1.9, 2.2 and 2.5 ms-1 increased with age and anthropometry, but no changes were found at 1.3 and 1.6 ms-1. Stepwise regression revealed passive drag best predicted net active drag at velocities of 1.3, 1.9, 2.2 and 2.5 ms-1. Results supported the Froude number theory that increased height will reduce wave-making drag

Swim Positioning and its Influence on Triathlon Outcome

Questions have been raised regarding which of the three legs of a triathlon influences the final finishing position. Some coaches subjectively believe that the swim and run are more important than the cycle, especially since the introduction of drafting during the cycle. This study analysed race position shifts between each of the three disciplines to assess the importance of the swim finish position and final finish position during draft legal Olympic distance triathlon events. Ten male and 10 female triathlon world cup events during one season were analysed. The results suggested that the triathlon swim leg is important because the winner exited the water in the first pack in 90% of elite male and 70% of elite female races. Correlations were also derived from finishing order for the whole triathlon and a finishing order that included the swim only, cycle only or run only time. For men, the average correlations for final finishing order with each of the swim, cycle and run, respectively, were 0.49, 0.67 and 0.86 and for the women; average correlations were 0.39, 0.67 and 0.85. Hence, this indicated that it was important to exit the water in the first pack and run well after cycling to achieve a successful final finishing position